Mohamad-Ziad Charif - Antares

Figure 6.19: The estimation of the background in the direction of the Sun as afunction of ∆(θ). The scrambled data in addition to the MC are presented here. Acut of χ 2 < 0.9 was applied here.6.4.2.3 Search variables and optimizationThe search variables that will be used in this analysis are still the same that wereused before (with the substitution of ∆(Ψ) by ∆(θ)). In addition, this time a newcut based on Nhit is going to be introduced in the analysis. However, we will notuse Nhit as an optimized cut, the optimization will follow as before with slightvariation:• χ 2 focus region is going to be between 0.7 and 1.2 .• ∆(θ) focus region will be between 0 ◦ and 20 ◦ .• For each χ 2 cut and dark matter model calculate Nhit max which the value ofmaximum value of the Nhit variable for the specific dark matter model.• Apply χ 2 & Nhit max cut on the scrambled data and then proceed to estimatethe background in the direction of the Sun.• Search for the optimal ∆(θ) cut for the optimal value of ¯Φ 90% .• Repeat the process for the entire focus region of χ 2 , and then select the bestvalue of all optimal values of ¯Φ 90% .The use of Nhit max is tailored specifically for low mass WIMPs as they are producelow energy neutrinos which in turn leave a lower number of hits on the detector.128